Can body and longitudinal seam therefor



Dec. 9, 1952 'Eil'ed March 23, 1949 H. F. JOHNSON 2,620,942

CAN BODY AND LONGITUDINAL SEAM THEREFOR 2 SHEETSSHEET 1 IN VEN TOR.

1527i? fa/ms)? BY a 47 7 012 [Iii S.

Dec. 9, 1952 H. F. JOHNSON CAN BODY AND LONGITUDINAL SEAM THEREFOR 2 SHEETS-SHEET 2 Filed March 23, 1949 H Z m ZZM W Patented Dec. 9, 1952 UNITED STATES PATENT OFFICE CAN, BODY AND LONGITUDINAL SEAM I HEREFOR ll Claims.

My present invention relates to sheet metal can bodies and to the making thereof and aims to provide certain improvements therein. More particularly, it relates to, a novel side seam in a can body and to the method of forming the same.

In the manufacture of sheet metal cans for packaging various items, and particularly in the manufacture of sheet metal cansfor packaging foodstuffs and the like,w herein nomcontzimination of the contents is an important problem, it is the current practice to utilize, what is known as a can body machine comprising a body maker and a side seamer. Such a body maker usually receives a supply of blanks from a'stack. and successively passes such blanks through 5 to 7 stations whereat successive operations are performed on each sheet metal blank tov form it into a can body. The operations customarily performed at these various stations comprise feed: ing, notching and edging of the blank, and then forming theprepared blank into acan body. One or more idle stations are usually provided between the feeding and notching stations, and idle stations are also usually provided between the notching, edging and forming stations.

At the notching station of such a can body maker, the corners on one end of the blank are notched or cut away, and the other end of the same blank is simultaneously provided with corresponding slits o r incisions. At the edging sta tion the end portions of the blank between the incisions on one end and the notches on the other end are bent back in opposite directions so as to provide oppositely-turned hooks which may be interlocked when the blank is wrapped around the horn at the forming station. At the forming station the blank is wrapped around the conven .tional horn to assume the general shape of the can body, the oppositely turned'edges of the blank or hooks are interlocked, and such hooks are bumped to form the conventional side seam of the can body. After the side seam is formed and bumped, the can body is moved to and along the side seamer where the conventional rotary solder roll is utilized to provide the necessary solder to sweat-solder the side seam. The can body is then transferred to a flanger where the top and bottom edges of the can body are flanged outwardly to receive the can ends and for the subsequent operation of double seaming.

In the formation of can bodies on machines of thetype above described, it has been found that due to the raw edges at the ends of the blank and the step-down of metal thickness at said ends in forming the seam, minute unsoldered pinholes frequently re formed in the side seam. It has also been found, after the soldering operation, that minute holes have been formed between the can ends and the side seam at the inner corners of the notches, and that such small holes, in fact, expose a raw edge of the can body. The minute holes in the side seam and the minute holes which occur at the notched corners both provide air leaks which facilitate contamie nation of the contents of the can.

Among the objects of my invention are: To form a novel sheet metal seam; to form can bodies without notching or slitting the blank and thereby to eliminate the cause of leaks, at the ends of the locked seam; to increase the strength or" the can when soldered; to provide a locked lap seam which is considerably stronger than the standard lock seam; to provide a can body where variations in the gauge of the metal used will have no efiect upon the resulting seam, and gen"- erally. to improve the construction of sheet metal cans and to reduce the cost thereof.

The. foregoing and other objects of my invention not specifically enumerated I accomplish by forming at one of the lap ends of a can body blank a longitudinally extending flange terminating in spaced relation to the to and bottom edges of the blank and at the other lap end of the blank a drawn groove which likewise terminates short of the top and bottom edges of the blank, engaging the flange within the groove, and then forming. a lock seam between the flange and the. walls of the, groove. Preferably the flange and the groove are simultaneously formed in interengaging relation and are then folded back to provide a, lock seam, which may there'- after be solderedor left unsoldered, depending upon the intended use of the can. At the opposite ends of the lock seam the lap' ends of the metal of the body progressively. diminish in ovefrlap so that at the topand bottom'edg'' portions of" the formed can body there are only two overlap thicknesses of metal analogous to standard practice for seaming the can ends onto the body. The invention will be better understood from the detailed description which follows, when considered in connection with the accompany ing drawings, wherein:

Figure 1 is a l n view of a metal blank from which the can body is formed. Fig. 2 is a side elevation of a can body formed from the blank shown in Fig. l and particularly showingthe side seam of the can.

'Fig'. 3 is a section on an e nlarged scale taken along the plane of the line 3- 3 of Fig. 4 is a perspective view of a portion of a can body at the side seam thereof with a part being broken away to better show the side seam formation.

Fig. 5 is a view similar to Fig. 4 showing the side seam after it has been indented to provide a flush outside seam.

Fig. 6 is a side elevation of a can body embodying the features of my invention and having annular reinforcing beads.

Figs. 7, 8 and 9 diagrammatically show the manner in which the side seam shown in Fig. 3 may be formed by complemental dies of a can body making machine.

Fig. 10 is a perspective view showing the relationship of the elements of a can body making machine, used in the side seam forming operation.

In the drawings the same reference characters designate corresponding parts in the various figures.

A can body I5 having a longitudinal side seam l5 embodying the present invention is preferably formed from a rectangular sheet metal blank I! by forming at one of the ends thereof an outwardly directed flange l8 and at the other end portion of the blank an outwardly directed groove IS, the flange l8 and the walls and 2| of the groove being, coextensive, interengaged, lock seamed, and folded back against the end portion 22 of the blank end formed with the groove l9 and against the body portion of the blank adjacent the end formed with the flange [8. The flange l8 and the groove l9 terminate at their opposite ends short of the edges 23 and 24 of the canbody and the metal at the ends of the blank between said edges and the ends of the flange, and the ends of the groove respectively is uncut,

unflanged, ungrooved and integral with the flanged and the grooved portions, respectively, and in single thickness overlying relation.

The longitudinal side seam l6 may be formed in any preferred manner and may be soldere'd'or not, as desired, depending upon the character of the contents to be packaged in the can. The seam l6 between the approximate points 25 and 25a on Fig. 2 is constituted by at least four thicknesses'of metal bearing against the can body and longitudinally beyond said points 25 and 2511 by lapped single thicknesses of metal.

Preferably the flange l8 and the groove l9 are simultaneously formed by a die unit of a can body making machine comprising a reciprocable pressure foot 26 movable into engagement with the lapped ends of the blank for clamping them against a horn or body former 26a, a male die or punch 21, a female die 28 having a socket which preferably is wider than the combined width of both the punch and three thicknesses I8, 20 and 2| of the metal blank as particularly seen in Fig. 7, and flanking said socket spaced protruding lips 28a and 28b for contacting and engaging spaced portions of the outer lap of the blank, thereby to provide two hold-downs for the lap portions of the blank, namely, by the lip 28a and the outer pressure foot 26, and a single hold-down by the lip 28b during the drawing operation, the punch and die being reciprocable in the same direction as the pressure foot 26.

and a transversely reciprocable slide 29 which may be moved in timed relation to the reciprocation of the punch and the die, respectively.

In the operation of forming the flange l8 and the groove [3, the pressure foot 26 is first moved into engagement with the lapped ends of the blank as shown at 22 in Fig. '7 and clamps such ends against the horn 26a or any other suitable member. The female die 28 is then moved into clamping engagement with the blank and the male die or punch 21 is moved into the socket in the female die and performs simultaneously a flanging operation on the inner lap to provide the flange l8, and a bending and drawing operation on the outer lap 20, to provide the groove IS in the outer lap. The female die and the punch are next withdrawn, as shown in Fig. 8, the pressure foot 25 remaining in clamping engagement with the overlapped end portions to provide the necessary hold-down pressure while the transversely movable slide 29 moves inwardly and bends the walls 20 and 2| and the flange l8 to form the partially completed seam as shown in Fig. 8. The slide 29 is then withdrawn, the female die 28 is moved into engagement with the partially completed seam, the end of the lip 28a of said die serving to bump the seam into the final side seam as shown in Fig. 9.

In the course of the drawing operation the grooved end of the blank has its top and bottom edges 30 and 3| (Fig. 2) drawn inwardly toward each other and out of true alignment with the edges 23 and 24, and the end portion 22 of the blank beyond the groove I 9 has its edge drawn inwardly between the extreme ends of the top and bottom edges 30 and 3| as shown at 32 in Fig. 2. In view of the inward drawing of the top and bottom edges as shown at 30 and 3|, the equivalent of chamfers at said lapped ends of the blank are provided, thus preparing the outer edges 30 and 3! so they will not project beyond the edges 23 and 24 during the flanging of the can body.

Instead of making the can body with a single interengaging lock seam extending substantially the full height of the can, under certain circumstances, for example, in large size cans which may require beaded reinforcement intermediate the ends thereof, the lock seam may be interrupted by a simple overlap of the end portions of the blank to facilitate the formation of the beads. The can body shown in Fig. 6 is of such type and has a plurality of longitudinally-aligned lockseamed portions l'6a between approximately each pair of points 33 and 33a, said portions being spaced apart by simple lapped portions 34 intermediate the ends of the can body and by simple lapped portions 35 at said ends of the can body. The lock-seamed portions I 6a may be simultaneously formed in exactly the same manner as is the lock seam l6 of Fig. 2 by using either a bank of dies or a multiple die unit of the character shown in Fig. 10. The simple lapped portions 34 will thus provide comparatively little resistance to the formation of reinforcing beads 36, which may be formed in the can body in any well known manner.

It will also be observed that the present invention particularly lends itself to the provision of a can body having a flush outside seam. After the seam has been interlocked by the female die 28, as shown in Fig. 9, it can again be bumped in a subsequent operation after forming, and preferably before soldering, to indent the seam and to provide a flush outside seam as shown in Fig. 5 of the drawings.

From the foregoing detailed description it will be appreciated that I have provided a novel form of seam for sheet metal parts and particularly for sheet metal can bodies and have disclosed on method and means of accomplishing the same. It will be understood, however, that variations in the character of the seam and in the method and means for producing the same may be resorted to within the range of engineering skill without departing from the spirit of my invention as defined in the appended claims.

What I claim is:

1. A sheet metal can body having a side seam, portions of which are provided by lapped single thicknesses of a sheet metal blank from which the can body was made, and other portions of which are provided by interengaging locked seamed parts on said end portion of the blank, the respective end portions of the blank being unnotched and free of incisions throughout the length of the seam.

2. A sheet metal can body having a side seam, the longitudinal end portions of said seam being provided by lapped single thicknesses of sheet metal at the end portions of a blank from which the can body was made, and an intermediate longitudinal portion of the seam being provided by interengaging lock-seamed parts on end portions of the blank, the respective end portions of the blank being unnotched and free of incisions throughout the length of the seam.

3. A sheet metal can body having a side seam, spaced longitudinal portions of which are provided by lapped single thicknesses of a sheet metal blank from which the can body was made, and the portions intermediate the lapped single thicknesses of metal are provided by interengaging locked seamed parts on said end portions of the blank, the respective end portions of the blank being unnotched and free of incisions throughout the length of the seam.

4. A sheet metal can body according to claim 3 wherein at least one of the portions of the side seam which is provided by lapped single thicknesses of metal is located between two portions of the side seam which are provided by interengaging locked seamed parts.

5. A sheet metal can body according to claim 4 wherein a portion of the side seam which is provided by lapped single thicknesses of metal and located between two portions of the side seam which are provided by interengaging locked seamed parts has a transversely-extending reinforcing beaded portion.

6. A sheet metal can body having a side seam, the longitudinal end portions of said seam being provided by lapped single thicknesses of sheet metal at the end portions of a blank from which the can body was made, and an intermediate longitudinal portion of the seam being provided by at least four thicknesses of sheet metal on end portions of the blank, said metal thicknesses being interengaged and lock-seamed, the respective end portions of the blank being unnotched and free of incisions throughout the length of the seam.

7. A partially overlapped and partially interlocked seam for joining together two sheet metal parts having edge portions free of incisions between said interlocked and overlapped portions of said seam, comprising a flange formed inwardly of the end of the edge portion of one part and a co-extensive complemental groove formed inwardly of the end of the edge portion of the other part, said flange and groove interengaged and lock-seamed, said edge portion beyond said flange and groove being in simple overlapped relation, and said flange and groove merging at one end with the overlapped portion of said seam.

8. A partially overlapped and partially interlocked seam for joining together two sheet metal parts having edge portions free of incisions between said interlocked and overlapped portions of said seam, comprising a flange formed intermediate the ends of the edge portion of one part and a co-extensive complemental groove formed intermediate the ends of the edge portion of the other part, said flange and groove interengaged and lock-seamed, said edge portion beyond said flange and groove being in simple overlapped relation, and said flange and groove merging at their ends with the overlapped portions of said seam.

9. A can body blank having edge portions adapted to be overlapped and interlocked to form a side seam, said body blank being free of incisions between the portions to be overlapped and the portions to be interlocked, one of said edge portions bent to provide a flange along part of said edge, the other of said edge portions provided with a co-extensive, complemental groove, said flange and groove adapted to be interengaged and lock-seamed and to provide a can body having a partially overlapped and partially interlocked seam.

10. A can body blank having edge portions adapted to be overlapped and interlocked to provide a side seam, said body blank being free of incisions between the portions to be overlapped and the portions to be interlocked, one of said edge portions being bent and drawn to provide a flange along part of said edge which merges uninterruptedly with the unflanged portion, the other said edge portion being drawn to provide a co-extensive complemental groove which merges uninterruptedly with the ungrooved part of said edge portion, said flange and groove adapted to be interengaged and lock-seamed and to provide a can body having a partially overlapped and par-. tially interlocked seam.

11. A sheet metal can body having a partially interlocked and partially overlapped side seam, said can body being formed from a metal blank having its marginal edges unnotched and free of incisions, one of said marginal edges intermediate its ends being bent outwardly to provide a flange, the other of said marginal edges being indented to provide a co-extensive, complemental groove, said flange and groove being interengaged and the flange and Walls of the groove being lockseamed, said edge portions beyond said flange and groove being in simple overlapped relation, and said interlocked and overlapped portions merging uninterruptedly one with the other.

HERBERT F. JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 285,283 Dolan Oct. 9, 1883 821,888 Ross May 29, 1906 831,118 Steward Sept. 18, 1906 1,217,667 Totterdale Feb. 27, 1917 1,912,259 Coyle May 30, 1933 1,917,174 Wilhelm July 4, 1933 2,183,738 Brenzinger Dec. 19, 1939 2,259,498 Taylor Oct. 21, 1941 2,323,349 Odquist July 6, 1943 2,365,112 Schrader et al. Dec. 12, 1944 

